Micro-electromechanical systems (MEMS), such as microaccelerometers, are used in a wide variety of applications. One such application is in vehicle airbag systems which deploy one or more airbags to protect vehicle passengers based on accelerations placed on the vehicle. Variable capacitance accelerometers have one or more electrodes on a stationary substrate and one or more electrodes on a mass constructed to move relative to the substrate when the mass is accelerated. An electrode on the mass and a corresponding electrode on the substrate form a capacitor, the capacitance value of which varies as the mass moves closer to or further from the substrate in response to acceleration. The sensitivity of variable capacitance microaccelerometers can be expressed as the relative change in capacitance between the sensor at rest and the sensor experiencing a given acceleration.
Accordingly, there is a need to design the sensitivity of capacitive microaccelerometers. For a given construction, it is often desirable to maximize the sensitivity. Also, it is desirable to design a family of capacitive microaccelerometers with different members of the family having different sensitivities without having to make radical design changes to the basic construction of family members.